Rotary pump



Feb. 22, 1955 G, GARNlER 2,702,509

ROTARY PUMP Filed Jan. 24, 1952 lll mvENToR: GEORGES GAmsR UnitedStatesPatent() ROTARY PUB/IP Georges Garnier, Asnieres, France, assignor toAir- Equipment, Asnieres, France, a French company Application January24, 1952, serial No. 267,949 claims priority, application France Api-ii6, 1951 4 claims. (ci. 10s- 126) This invention relates to newimprovements in lrotary pumps and more particularly in pumps of the gear type.

It is a well-known fact that the pressure at which gear pumps'can Ib-eused is limited in practice by the play on the outside diameter of thegears and, above all, by the lateral deformation of the lateral closuremember. This deformation increases with the rise in pressure and causesyleakage onthe gear faces. c

It -has heretofore been proposed to obviate this draw back by applyingthe pressure of a spring or even of the 'discharged liquidr itself tothe back face 4ofan axially adjustable end plate or bushing. However,this arrangement has the drawback that it necessitates a very precisefit of the gear axle bushings, in particular at the line where theflanges of two adjoining bushings meet, this meeting line beingensured-by a flat part machined With great precision in order to obtainacceptable stanchness of the um p Itpis an Iobject of the presentinvention to provide an improved construction of a rotary pumpcomprising wear compensating elements intended to prevent leakages onthe faces of the rotors, which elements do not require a too precisefit, that is to say, which are as simple as possible in design.

With -this principal object in View, the invention consists according toits lbroadest aspect in a pump of the -type described above wherein asimple, non-sliding thin plate is applied agai-nst the axial ends of therotors by the delivery pressure of the pump.

Another object of the invention resides in the application, to a pump ofthis type, of means intended to restrict the effect of the dischargepressure applied.

With this object in view, the invention fur-ther consists in restrictingthe effect of the said `discharge pressure to annular zones on thecircumference of the said flexible thin plate, in particular Iby the useof annular sealing rings, preferably toric and made of elastic material.

Other characteristics and particular features of the present inventionwill lbecome apparent from the following description, which illustratestwo specific embodiments of an improved gear pump, the said embodimentsbeing disclosed merely as an indication, and shown diagrammatically onthe accompanying drawing forming a part 'of said description.

'In the drawing:

iFig. 1 is a section through the shafts of the two gears of a `firstembodiment of an improved gear pump;

iFig. 2 is a perspective View of certain of the elements of -the pumpshown in lrFig. l, separated from each other;

Fig. 3 is a similar view to that shown in Fig. 1, but of a secondembodiment of an improved gear pump;

iFig. 4 is a front view of the pump lshown in Fig. 3, the cover and thelateral supporting plate having been removed;

Fig. 5 is a section view along vthe line V-V of Fig. 4.

In the embodiment shown in Figs. 1 and 2, which relate -to a pump ofwhich .the lgears have no trunnions, `1 is the front `or Imain 4bearingin which are arranged a ball bearing 2 and a bush-ing 3 supporting thedriving spindle 4 of the pump; on this spindle `are keyed the drivingpulley '5 and the driving gear 6 in mesh with the driven gear 7. 8 isthe pump casing and 9 is the pump cover.

`On both sides of the pump gears `6 and 7 are end plates 10 and 11 `madeof a material with low coefficient of friction.

Stanchness is ensured Iby plate 'sealing rings 12, 13, 30

14 and 15, and by a bushing sealing ring 16, all of the 2,702,509 jPatented Fein-V22, 1955 'ice said rings being recessed in annularhousings, one of which, numbered 17, can be seen more particularly inFig. 2.

The end plate 10 has a hole 10a at the outlet of the bushing 3, thediameter of the said hole corresponding to the diameter of .the flange3a of the said bushing, the sealing ring 16 coming into contact bothwith the flange and with the plate in question, which ensures good tightness in the direction of the zone of junction of the bushing and plate,which are very easy to machine.

The cover 9 is provided with two annular grooves 9a and 9b,communicating with each other opposite the meshing zone of the gears,and serving to house elastic holding rings 18 and 19 which form packingjoints intended to limit the pressure surface on the plate 11 andtlensure slight initial pressure when the pump is running i `e.

Opposite the meshing zone of the pump gears the plate 1-1 is pierced bya hole 20 through which the pump discharge communicates with the annulargrooves 9a and 9b, which therefore causes the rear surface of the plate11 to be under the same pressure as the surface which is `in contactwith the face of the gears 6 and 7.

It will at once be realised that, whatever may be the deformation of thecover, the tightness of the pump is perfectly ensured on the gear faces.

In the embodiment shown in Figs. 3 to 5, which relate lto a pump ofwhich the gears have trunnions, 21 is the front or main bearing, 22 thepump cover. In these members are arranged the bushings 23, 24, 25 and 26for the journals 27a, 27b of the driven gear 27, for the journal 28a ofthe driving gear 28, and for the driving spindle 29, on which the lattergear is keyed. 30 is the pump housing interposed between the members 21and 22.

The faces of the gears 27 and 28 are in contact with the plates 31 and32, which are made of a material having a low coefficient of friction.Annular gaskets 33, 34, 35, l36, 37, 38 and 39, arranged in grooves (40on Fig, 4) in the members 21, 22 and 30 ensure tightness against leakagetowards the outside.

The plates 31 and 32 are (as in the case of the single plate 11 in thepreceding example) held in place on their rear surface by elasticholding rings 41, 42, 43 and 44, which fill the same function as therings 18 and 19 in the preceding example. Here again, the rear surfaceof each plate communicates with the discharge of the pump through anorifice 45.

In order to simplify machining, the bushings 23, 24, 25 and 26 have noanges fitted into the holding plates. The latter rest directly againstthe front surface of each bushing.

.While the invention has been disclosed in connection with certainspecific embodiments thereof, it is to be understood that these are byway of example rather than limitation.

What I claim is:

1. Ina pump of the character described, a pump housin g having front andrear walls, at least a rotor within said housing, a wear control platein said housing associated with s aid .rotor on at least one axial facethereof, said plate 4being interposed between said face of said rotorand the adjacent wall of said housing and having the edge thereof fixedto said housing, said plate being further resilient, elastic and capableof being deflected so that it can be urged toward said face of saidrotor by a Ihuid pressure, an annular groove in said adjacent Wall, asealing ring of a smaller transverse section than. that of said groovehoused in said groove and adapted to engage fluidtight-ly the inner`side of said groove and the adjacent face of said plate facing towardsaid inner side of said groove so that said fluid pressure may act onlyon an annu-lar part of said adjacent face, means for supplying fiuidpressure to said groove to urge the opposit-e side of said annular partof said plate into sealing engagement with the adjacent part of theaxial face of said rotor.

2. In a pump of the character described, a pump housing having front andrear walls, at least a rotor within said housing, a wear control platein said housing associated with said rotor on at least one axial facethereof, said plate being interposed between said face of said rotor andthe adjacent` Wa1l-oi:` saidV housing and havingthef edge thereof Xed tosaid housing, said plate being further resilient, elastic and capable ofbeing deflected so thataitcan-'beurgedtowardfsaid fac-e of said rotorbyy aiuidcpressure, .an annulargroove in said adjacentt'wall, a sealingring of a smaller transverse section than that ofsaid groovehoused insaid groove and adapted to engageruidtightly; the innerside of saidgroove and the adjacentsface ofsa-id plate facing toward said inner sideof said groove sothat said uid pressure may act only on an annularpartof said adjacent face, said plate having, a hole therein one end thereofopening on the discharge sidel of said pump .and the other end openinginto said groove whereby Huid pressure from the discharge side ofsaidpump may. be supplied to said groove-to urge thev opposite side `of saidannular part of said plate into sealing engagement with the adjacentpart of the axial face of said rotor.

3. In a p ump4 ofthe. gearV type, a pump housing having front and rearWalls, at least a pair of gear members in meshing engagement withA oneanother, a wear control platein said-.housing associated with said gearmembers on atleast one axial face of said gear members, said plate beinginterposed between said face of said gear members and, theV adjacentWall of said housing: and having the edge thereof fixed to saidhousing,- said plate being further resilient, elastic and capableY ofbeing deflected so that it can Aberurged toward said faceV of said rotorby a uid pressure, annular grooves in said adjacent wall coaxial Witheach of said gear members and communicating with eachother, a sealingring of a smaller transverse section-than that of said grooves, housedin each of said grooves and adapted to engage iluidtightly the innerside of said grooves and theadjacent face of said plate facing towardsaid inner sideA ofl saidv grooves so that said iuid pressure mayactonly on an annular part of said adjacent,V face, means for supplyingfluid pressure to said grooves to urge the opposite side of said annularpart of said'v plate into sealing engagementwith the adjacent part ofthe axial face of said gear members.

4.- In a pump of the gear type, a pump housing having front andfrearwalls, at least a pair of gear members in meshing engagement with oneanother, a wear control plate infsaid housing associated with said gearmembers on at least one axial facefof said gear members, said platebeing interposed between said face of said gear members and the adjacentwall of said housing, and having the edge thereof fixed to saidhousing,said plate being further resilient, elastic ande'apable of beingdeilected so that it can be urged. towardsaid face of said rotor by auid pressure, annular grooves in said adjacent wall coaxial with'each ofsaid gearA membersv andcommunicating withreach other, a sealing ring ofa* srnaller'- transverse section than that of said groove, housed ineach of said grooves andadaptedto engage il'uidtightly the inner side ofsaid grooves and the adjacent face of said plate facing toward saidinnersideof said grooves'so 'that said fluid pressure mayact only on anannular part of said adjacent face, said plate having a hole therein oneend thereof opening on the discharge side of said pump and the other endopeningfinto saidv grooves-wherebyiluid pressure from the dischargesideof said pump,1 may be supplied between said plate and said Walltourgerthe opposite side of said annular part of said plate'into sealingengagement with -the adjacent part of the axial face of vvsaid' gearmembers.

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